1831811661 has 6 divisors (see below), whose sum is σ = 2645950190. Its totient is φ = 1221207768.

The previous prime is 1831811647. The next prime is 1831811671. The reversal of 1831811661 is 1661181381.

It can be written as a sum of positive squares in only one way, i.e., 1727649225 + 104162436 = 41565^2 + 10206^2 .

It is not a de Polignac number, because 1831811661 - 2¹¹ = 1831809613 is a prime.

It is a super-2 number, since 2×1831811661² = 6711067922751157842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1831811671) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 101767306 + ... + 101767323.

Almost surely, 2^1831811661 is an apocalyptic number.

It is an amenable number.

1831811661 is a deficient number, since it is larger than the sum of its proper divisors (814138529).

1831811661 is a wasteful number, since it uses less digits than its factorization.

1831811661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 203534635 (or 203534632 counting only the distinct ones).

The product of its digits is 6912, while the sum is 36.

The square root of 1831811661 is about 42799.6689356355. The cubic root of 1831811661 is about 1223.5647020769.

The spelling of 1831811661 in words is "one billion, eight hundred thirty-one million, eight hundred eleven thousand, six hundred sixty-one".